1. Field of the Invention
The present invention relates to a servo motor having an operating member, by which a rotary shaft of the servo motor is capable of being rotationally operated by hand (manually) from a location outside of the servo motor.
2. Description of the Related Art
A servo motor has been utilized, for example, as a drive source for a robot or an actuator or the like. In this type of servo motor, a detecting device for detecting an angle of rotation of a rotary shaft is provided, together with a rotor that rotates integrally with the rotary shaft, and a stator, which is separated a given distance and arranged in confronting relation to the rotor. (See, Japanese Laid-Open Patent Publication No. 11-332180.)
Normally, such a servo motor is driven by being electrically energized from an external power source. However, in the event that electricity is interrupted as a result of abnormal stoppage of the apparatus on which the servo motor is mounted, it becomes difficult to operate (actuate) the servo motor. Consequently, in such a state, methods have been considered for actuating the servo motor by application of an external force at the side (load side) of the apparatus that is driven by the servo motor.
However, generally, a servo motor is constructed such that the gear ratio thereof is elevated, whereby the rotational torque of the servo motor is increased, so that the thrust force provided by a feed screw can be enlarged. Owing thereto, in many cases, manual operation of the apparatus side, or even carrying out fine positional adjustments, is quite difficult, and cases can also be presumed in which manual operations of the servo motor are completely impossible. In the case that manual operations from the apparatus side cannot be performed, an operation is required by which electrical energy is applied temporarily to the servo motor. However, such an operation is burdensome, and naturally, cases also exist in which the supply of electrical energy may be impossible.